The present invention relates broadly to the manufacture of vinyl-backed floor coverings and more particularly to a process of assembling a floor covering having a vinyl layer intermediate a woven or tufted carpet layer and a backing layer.
Carpet is manufactured through a series of separate processes that are typically carried out on separate manufacturing lines. A first line is used to produce a carpet material that is formed either by weaving textile yams to form a woven layer or by attaching tufts of textile material to a woven primary backing. In either case, a thin polymeric locking layer is coated to the backside. The output of this process is an unbacked or unfinished carpet material, which is then wound into a roll and transferred to a second processing line. In the second processing line, a layer of vinyl material is added to the back of the carpet to fill the voids in and between the fibers and to provide a uniform surface for attachment of a backing layer. This vinyl layer is typically formed by applying an uncured layer of vinyl on a belt, pressing the unbacked carpet material onto the vinyl sheet and passing the assembly through an oven to cure the vinyl layer in place. Once the vinyl layer has been cured, the carpet/vinyl is separated from the belt and again wound into a roll for transfer to a third processing line where a backing layer is adhered to the vinyl layer.
This typical manufacturing process is highly inefficient in that it requires a separate process line for the vinyl casting process. In addition, the method used to apply the vinyl layer requires the use of a relatively thick layer of vinyl. The cost of virgin vinyl is such that a reduction in the thickness of this layer would result in a significant overall cost reduction for the final product.
It is therefore highly desirable to incorporate a vinyl casting process that would reduce the amount of virgin vinyl required to manufacture the carpet product and that would eliminate the need for a separate vinyl casting processing line.
Accordingly, it is an objective of the present invention to provide a method of assembling a vinyl-backed floor covering wherein the finishing sub-processes are joined in a single continuous production line.
It is another objective of the present invention to provide a method of finishing a vinyl-backed carpet product with a reduced virgin vinyl material content.
It is yet another objective of the present invention to provide an improved method of applying a reinforced layer of vinyl plastisol or other polymeric material to a textile sheet.
Toward these ends, a method of assembling a floor covering according to the present invention comprises providing a carpet layer having textile fibers defining an upper surface and having an opposing carpet layer back surface. The method further comprises forming a vinyl layer on the carpet layer back surface and adhering a backing layer to the vinyl layer, the backing layer having a front backing surface for adhering to the vinyl layer and an opposing rear backing surface. According to this method, the carpet layer is provided as a continuous sheet and the steps of forming a vinyl layer and adhering a backing layer are performed on the carpet layer in a continuous manner in a single carpet finishing line.
A method of assembling a floor covering according to the present invention may further comprise the step of applying an adhesive to the rear backing surface, wherein this step is performed in a continuous manner in the single carpet finishing line. The adhesive is preferably an oleophobic pressure sensitive adhesive. Where an adhesive is applied, it is preferred that the method further include the step of applying a release cover over the adhesive to prevent inadvertent adhesion of the adhesive prior to installation of the floor covering.
A method of assembling a floor covering according to the present invention may comprise the step of applying a barrier layer to the rear backing surface, the barrier layer having an upper barrier surface adjacent the rear backing surface and a lower barrier surface. The barrier layer is effective for substantially inhibiting migration of moisture from a substrate into the backing layer and for substantially inhibiting migration of backing constituents from the backing to the substrate. The method may further comprise applying an adhesive to the rear barrier surface. The barrier surface in this variation would be effective for substantially inhibiting migration of backing constituents from the backing to the adhesive.
The carpet layer in a method of assembling a floor covering according to the present invention may include a resin composition layer having a front resin surface adhered to at least a portion of the textile fibers and an opposing back resin surface. The carpet layer may include a primary backing to which the textile fibers are attached, the resin composition layer being formed so as to lock the textile fibers to the primary backing. Alternatively, the textile fibers of the carpet layer may be configured as interwoven warp and weft yarns which form a woven carpet fabric having a traffic surface and an opposing rear fabric surface. The warp and weft yarns of the woven carpet fabric define interstices therebetween. The resin composition layer is preferably formed on the rear fabric surface so that a portion of the resin composition layer occupies at least a portion of the interstices.
In a preferred method of assembling a floor covering according to the present invention, the step of forming a vinyl layer includes continuously moving the carpet layer through a vinyl application station. This method further includes depositing a first portion of uncured vinyl material on the carpet layer back surface and spreading the first portion of uncured vinyl material across the carpet layer back surface. The method also includes the step of establishing a substantially uniform predetermined thickness of the vinyl layer. The step of establishing a substantially uniform predetermined thickness preferably includes passing the carpet layer through means for removing excess vinyl material and controlling the thickness of the vinyl layer. The step of establishing a substantially uniform predetermined thickness may include passing the carpet layer between a thickness control roller and a base surface in a predetermined direction. The thickness control roller is configured for engaging and spreading the vinyl material across the carpet layer back surface to provide a substantially uniform vinyl layer. The control roller layer has an outer surface, a portion of which is in contact with the vinyl material and preferably is rotated at a predetermined rate in a direction such that the portion of the control roller surface in contact with the vinyl material moves in a direction opposite to the predetermined direction of motion of the carpet layer.
The step of forming a vinyl layer in a method of assembling a floor covering according to the present invention may include applying a scrim sheet over the first portion of uncured vinyl material spread on the carpet layer back surface and depositing a second portion of uncured vinyl material over the scrim sheet.
The step of forming a vinyl layer in a method of assembling a floor covering according to the present invention preferably further includes heating the uncured vinyl material to a temperature above the cure temperature of the vinyl material to cure the vinyl layer and permanently adhere the vinyl layer to the carpet layer back surface.
The vinyl layer formed in the methods according to the present invention is preferably formed from a polyvinyl chloride plastisol material.
An illustrative method of assembling a floor covering according to the present invention comprises providing a carpet layer having textile fibers defining an upper surface and having an opposing carpet layer back surface. This illustrative method further comprises depositing a first portion of uncured vinyl material on the carpet layer back surface and spreading the first portion of uncured vinyl material across the carpet layer back surface. The method still further comprises applying a scrim sheet over the first portion of uncured vinyl material and depositing a second portion of uncured vinyl material over the scrim sheet. The carpet layer is then passed between a thickness control roller and a base surface in a predetermined direction. The control roller has an outer surface, a portion of which engages the second portion of uncured vinyl material. The control roller is rotated at a predetermined rate in a direction such that the portion of the control roller surface engaging the vinyl material moves in a direction opposite to the predetermined direction of motion of the carpet layer, thereby establishing a vinyl and scrim laminate having a substantially uniform thickness. The illustrative method also comprises heating the uncured vinyl material to a temperature above the cure temperature of the vinyl material to cure the vinyl and permanently adhere the vinyl and scrim laminate to the carpet layer back surface. A backing layer is adhered to the vinyl layer, the backing layer having a front backing surface for adhering to the vinyl layer and an opposing rear backing surface. The carpet layer is preferably provided as a continuous sheet and the steps of depositing a first portion of uncured vinyl material, spreading the first portion of uncured vinyl, applying a scrim sheet, depositing a second portion of uncured vinyl material, passing the carpet layer between a thickness control roller and a base surface, heating the uncured vinyl material; and adhering a backing layer are preferably performed on the carpet layer in a continuous manner in a single carpet finishing line.
A method of applying a polymeric material to a textile sheet having opposed first and second surfaces according to the present invention comprises the steps of forming a plastisol from the polymeric material, depositing a first portion of plastisol on the first surface of the textile sheet and spreading the first portion of plastisol across the first surface of the textile sheet. The textile sheet is passed between a thickness control roller and a base surface in a predetermined direction. The control roller has an outer surface, a portion of which engages the plastisol. The control roller is rotated at a predetermined rate in a direction such that the portion of the control roller surface engaging the plastisol moves in a direction opposite to the predetermined direction of motion of the textile sheet, thereby establishing a layer of polymeric material having a substantially uniform thickness. The method preferably further comprises the step of heating the plastisol to a temperature above the cure temperature of the polymeric material to cure the polymeric material and permanently adhere the polymeric material to the textile sheet.
A method of forming a laminate having a textile sheet with opposing first and second surfaces, a first polymeric composition layer adhered thereto, a reinforcement sheet and a second polymeric composition layer according to the present invention comprises the steps of forming a plastisol including at least one polymeric resin material and depositing a first portion of plastisol on the first surface of the textile sheet. The method further comprises applying a reinforcement sheet over the first portion of plastisol and depositing a second portion of plastisol over the reinforcement sheet. The textile sheet is passed between a thickness control roller and a base surface in a predetermined direction. The control roller has an outer surface, a portion of which engages the second portion of plastisol. The control roller is rotated at a predetermined rate in a direction such that the portion of the control roller surface engaging the plastisol moves in a direction opposite to the predetermined direction of motion of the textile sheet, thereby establishing a substantially uniform overall thickness of the laminate. The method preferably further comprises the step of heating the plastisol to a temperature above the cure temperature of the polymeric material to cure the polymeric material and permanently adhere the polymeric material to the textile sheet. The reinforcement sheet in a laminate formed by this method may be a fiberglass scrim material.